Propensity of raw victorian brown coal for physical adsorption of nitrogen, oxygen, carbon dioxide and wat

The sorption properties of samples of H-ZSM-5 zeolite and their forms modified with P, B and Mg were determined by the physical adsorption of nitrogen and evaluated by BET isotherm and t-plot methods. The diffusivities of the samples were measured using a new flow gravimetric method involving the sorption of p- and o-xylenes. The BET specific surface area decreased from 358 m2/g to 35–90 m2/g mainly because of a decrease in micropore volume as determined by the t-plot method. The rate of sorption of p-xylene on all the samples investigated followed Fick's second law of diffusion, leading to an effective diffusivity of ca. 1.7 × 10−11 m2/s, irrespective of whether the H-form or the modified forms were investigated. The sorption isotherms for o-xylene showed some unusual steps. Values for the effective diffusivities decreased from 2.6 × 10−12 m2/s for the H-form to 2.0–2.3 × 10−12 m2/s for the modified forms. The equilibrium concentration of o-xylene at P/P0 = 0.1 was only 0.38–0.68 mol/unit cell, while that of p-xylene was 4.40–5.98 mol/unit cell.

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Potential Evaluation of Gray Clay as Adsorbent of Heavy Metals Zinc (II) and Lead (II)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.798-799.622 ◽

2014 ◽

Vol 798-799 ◽

pp. 622-627

Author(s):

Wellington Siqueira Lima ◽

José Vanderley Nascimento Silva ◽

Aline Cadigna Lima Patrício ◽

Guilherme Costa Oliveira ◽

Meiry Glaúcia Freire Rodrigues

Keyword(s):

Heavy Metals ◽

Factorial Design ◽

Metal Removal ◽

Physical Adsorption ◽

X Ray Diffraction ◽

X Ray ◽

Removal Capacity ◽

Adsorption Of Nitrogen ◽

Potential Evaluation ◽

Good Percentage

The problems caused by contamination of heavy metals generate a growing need to implement technologies to reduce or eliminate them. This work aims to evaluate the potential of gray clay, the process of removal of zinc and lead from synthetic effluents in finite bath system. The clay was characterized by: X-ray diffraction, X-ray Spectroscopy Energy Dispersive and Physical Adsorption of Nitrogen. The tests were performed finite bath following a 22 factorial design, with the variables: pH and initial concentrations of metal. The clays were evaluated for their removal capacity and rate of metal removal. After the characterization and evaluation, it was found that the gray clay comprises clay of the groups of kaolinite and mica. The results of the factorial design shown that the adsorption of the metals zinc and lead can be developed with good percentage of removal.

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Non-isothermal Adsorption of Nitrogen-carbon Dioxide Mixture in a Fixed Bed of Zeolite-X.

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN ◽

10.1252/jcej.27.45 ◽

1994 ◽

Vol 27 (1) ◽

pp. 45-51 ◽

Cited By ~ 23

Author(s):

Jong-Nam Kim ◽

Kuck-Tack Chue ◽

Kwon-Il Kim ◽

Soon-Haeng Cho ◽

Jong-Duk Kim

Keyword(s):

Carbon Dioxide ◽

Fixed Bed ◽

Zeolite X ◽

Isothermal Adsorption ◽

Adsorption Of Nitrogen

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On the concentration dependence of surface diffusion coefficients in capillary porous materials

Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences ◽

10.1098/rspa.1991.0095 ◽

1991 ◽

Vol 434 (1891) ◽

pp. 317-340 ◽

Cited By ~ 6

Keyword(s):

Experimental Data ◽

Carbon Dioxide ◽

Pore Size ◽

Surface Diffusion ◽

Diffusion Coefficients ◽

Physical Adsorption ◽

Structural Heterogeneity ◽

Size Dependent ◽

Chemical Potentials ◽

Uniform Pore Size

The influence of structural heterogeneity, in the form of a non-uniform pore size distribution, on the isotherms and surface diffusion coefficients for monolayer physical adsorption is studied. A pore size dependent langmuirian isotherm is used along with consideration of equality of chemical potentials at the pore mouths at an intersection. The diffusion is modelled by a recently developed random walk formulation. It is found that the surface diffusion coefficients are strongly influenced by the heterogeneity and have a stronger increase with overall coverage than that predicted by the Darken equation. The results are found to match the experimental data of P. C. Carman and F. A. Raal on the diffusion of carbon dioxide in carbon black without the use of a fitting parameter.

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